10 SCREEN 1
15 x = -100
17 IF x = 0 GOTO 100


20 y = -(1 / 25 * x ^ 2)

25 z = x + 150
27 e = y + 150


30 PSET (z, e), 2
33 LINE (0, 150)-(300, 150), 1
37 LINE (150, 0)-(150, 300), 1

40 x = x + 1
45 IF x = 201 THEN 100

50 GOTO 20
100 END